Top roll loading system for drafting units

ABSTRACT

A guide arm of a top roll loading system of a drafting unit is pivotally mounted on a bracket, with the pivot thereof positioned a substantial distance below and rearwardly of the plane of all of the drafting rolls so that yieldable force applied to the guide arm is transmitted to the top rolls in an inclined downward and forward direction, as is particularly desirable where the back or feed top roll is offset rearwardly of the back or feed bottom roll of the drafting unit. Also, a novel compound linkage connects a yieldable force means to a latch arm pivoted on the guide arm and is so designed that a compression spring or a pressurized pneumatic bag or tube may be used alternatively as the yieldable force means therefor by a simple interchange of parts.

United States Patent (1 1 Staneff [54] TOP ROLL LOADING SYSTEM FORDRAFTING UNITS [75] Inventor: Stefan Staneff, Herzongenaurach,

Germany [73] Assignee: Industriewerk Schaeffler, OI-IG,

Herzongenaur'ach, Germany [22] Filed: June 16, 1971 [21] Appl. No.:153,608

[52] US. Cl ..l9/267, 19/295 [51] Int. Cl. ..D0lh 5/46 [58] Field Ofseillch ..l9/266, 267, 261, 19/295, 258

[56] References Cited UNITED STATES PATENTS 840,779 H1907 Libby ..19/26I3,310,848 3/1967 Stahlecker et al ..l9/267 3,568,258 3/1971 Schiltknechtet al ..I9/295 1 3,732,596 May 15, 1973 FOREIGN PATENTS OR APPLICATIONS732,939 6/l955 Great Britain l9/258 Primary ExaminerDorsey NewtonAttorney- Warley L. Parrott ct al.

[57] ABSTRACT A guide arm of a top roll loading system of a draftingunit is pivotally mounted on a bracket, with the pivot thereofpositioned a substantial distance below and rearwardly of the plane ofall of the drafting rolls so that yieldable force applied to the guidearm is transmitted to the top rolls in an inclined downward and forwarddirection, as is particularly desirable where the back or feed top rollis offset rearwardly of the back or feed bottom roll of the draftingunit. Also, a novel compound linkage connects a yieldable force means toa latch arm pivoted on the guide arm and is so designed that acompression spring or a pressurized pneumatic bag or tube may be usedalternatively as the yieldable force means therefor by a simpleinterchangc of parts.

15 Claims, 9 Drawing Figures PATEME MAY 1 5 ms sum 1 0r 4 PATENTEI] HAY]SE73 SHEET 3 BF 4 TOP ROLL LOADING SYSTEM FOR DRAFTING UNITS Thisinvention relates to drafting units for roving frames, spinning frames,and the like, and is particularly concerned with loading or weightingmeans for the top rolls of such drafting units.

Heretofore, such drafting units generally have been provided with aloading system including a pivoted guide arm carrying front andrear'saddles to which the usual holders or support blocks for the topdrafting rolls are adjustably secured for varying the spacing be tweenadjacent top rolls. Various forms of releasable pressure means have beenproposed heretofore for applying downward pressure to the pivoted guidearms of such loading systems to, in turn, load the top rolls while theyoccupy operative positions over the bottom drafting rolls.

As far as is known, at least those top roll loading systems which havenot been equipped with individual springs or other individual pressuredevices for each top roll heretofore, have been so constructed as toapply pressure to the top rolls only in a downward di rectionsubstantially perpendicular to the mean path of travel of the textilefibers being drafted through the drafting units. However, there areinstances in which it is desirable to apply such pressure in a directioninclined forwardly and downwardly, as for example, when the loadingsystem is used with a drafting unit of the type having at least therearmost or back feed roll of its top rolls offset rearwardly of thecorresponding bottom feed roll. Also, it is desirable that the effectivepressure being applied to each top drafting roll is adjustable withoutnecessarily providing an individual pressure device or spring means foreach top roll.

It is therefore an object of this invention to provide a loading systemfor the top rolls of a drafting system including a pivoted guide arm andmeans for applying a generally downward yielding force to the guide am,but wherein the arm is so mounted that such force is transmitted to thetop rolls in an inclined downward and forward direction, andadditionally wherein the guide arm has a rear saddle for the top feedroll pivotally connected thereto, with a front saddle for theintermediate and front top roll being pivotally connected to the rearsaddle, in such a manner that the pivots are selectively positionable tovary the moment of force applied to each top drafting roll.

It is another object of this invention to provide a top roll loadingsystem of the character described including a support bracketstationarily mounted rearwardly of the drafting rolls, and wherein therear portion of the guide arm is pivotally connected to the bracket formovement about an axis spaced a substantial distance below the meanplane of the path of travel of the textile fibers being drafted throughthe drafting unit so that, when a yieldable force is applied to theguide arm tending to pivot the same downwardly about its axis, thepressure is transmitted to the top rolls in an inclined downward andforward direction.

Still another object of this invention is to provide a top roll loadingsystem of the character last described including improved means fortransmitting pressure or force from a yieldable force means to the guidearm and comprising a compound linkage having an upper lever and a lowerlever pivotally mounted on the aforementioned bracket and whose proximalportions overlap each other with the upper portion of the lower leverpositioned forwardly of the lower portion of the upper lever. Aforwardly projecting downwardly facing cam surface is provided on theupper lever above its pivot point, and a latch arm is pivotally mountedon the guide arm on an axis above and rearwardly of the cam surface andhas a locking element which is movable with the latch arm into and outof engagement with the cam surface. The yieldable force means urges thelower lever in one direction about its pivot so that its upper portionengages and urges the upper lever in the opposite direction about itspivot whereby the cam surface is biased forwardly and downwardly, andthe relationship of the locking element and the pivot of the latch am issuch that, when the locking element is engaging the cam surface, itbiases the guide arm downwardly thereby loading the top rolls of thedrafting unit. The latch arm may be pivoted upwardly relative to theguide arm so that the top rolls may be readily relieved of the loadthereon, and the guide arm then may be swung upwardly and rearwardly toan inoperative position with the guide arm.

Some of the objects of the invention having been stated, other objectswill appear as the description proceeds when taken in connection withthe accompanying drawings, in which FIG. 1 is a side elevation of adrafting unit, partially in section, showing the improved top rollloading system in association therewith;

FIG. 2 is a top plan view of the apparatus shown in FIG. 1;

FIG. 3 is an enlarged longitudinal vertical sectional view through thedrafting unit and the loading system with the bottom drafting rollsbeing shown in broken lines, and wherein the assembly of parts is shownin a different position from that of FIG. 1 for purposes of clarity;

FIG. 4 is a fragmentary vertical sectional view taken substantiallyalong line 4-4 in FIG. 3;

FIG. 5 is a fragmentary vertical sectional view taken substantiallyalong line 5-5 in FIG. 3;

FIG. 6 is a fragmentary rear elevation of the guide arm and associatedsupporting means therefor looking in the general direction of the arrowindicated at 6 in FIG. 3;

FIG. 7 is an exploded perspective view of the front and rear saddles,associated top roll holders and one of the top drafting rolls, removedfrom the guide arm of the loading system;

FIG. 8 is a fragmentary vertical sectional view similar to theright-hand portion of FIG. 3, but wherein the various parts shown inFIG. 8 occupy positions corresponding to FIG. 1, and showing the loadingsystem arranged to accommodate pneumatic pressure to serve as itsyieldable force means as an alternative to the compression spring meansof FIG. 3; and

FIG. 9 is a fragmentary vertical sectional view taken substantiallyalong line 99 in FIG. 8.

The loading system of this invention, although not limited thereto, isespecially useful in association with drafting units of the type havingone or more top rolls which are offset rearwardly of respective bottomdrive rolls. Therefore, referring more specifically to the drawings, thedrafting unit shown in FIGS. 1-3 includes three spaced bottom draftingrolls, namely, a bottom back or feed roll 11, a bottom intermediate roll12, and a bottom front or delivery roll 13. As preferred, the

bottom rolls are shown in the form of fluted rolls. Top drafting rolls11a, 12a, 13a are provided adjacent the respective bottom drafting rolls11, 12, 13, and to aid in controlling the fibers being drafted, thebottom feed roll 11 may be offset upwardly of the plane of bottom rolls12, 13. As preferred, the top rolls are shown in the form of cushionrolls. Although the three top rolls may be disposed in a substantiallycommon plane extending through the axes thereof, top feed roll 11a isoffset rearwardly of bottom feed roll 11 to form a nip therewith whichis spaced angularly rearwardly of the apex of feed roll 11 with respectto the mean plane of the path of travel or draft path" of the fibroustextile material T through the drafting unit. Suitable endless draftaprons 14, 14a may engage the respective rolls 12, 12a with the forwardportions of aprons 14, 14a engaging suitable cradle nose members 15, 15aadjacent the nip of delivery rolls 13, 13a to aid further in control ofthe fibers being drafted.

The improved loading or weighting system of this invention comprises aguide arm of hollow construction and which includes an elongate forwardportion or body 20a of inverted substantially U-shaped crosssectionalconfiguration and having a rear downwardly extending portion 20b thereonwhich straddles a stationarily mounted, hollow support bracket 21. Thetwo legs of the downwardly extending portion 20b of guide arm 20 arepivotally connected to the respective opposite side walls of bracket 21by substantially axially aligned pivot pins 22. It is important to notethat, although the pivot axis of guide arm 20 is shown in FIG. 1positioned above the level of all of the drafting rolls 1 1-13, 1 1a-13awhen the top rolls Ila-13a occupy the solid line, operative, positionedof FIG. 1, such axis, represented by pivot pins 22, is positioned asubstantial distance below the mean plane of the draft path through thedrafting unit, which plane is represented by the broken line P inFIG. 1. Stated in another way, the axis of guide arm 20 is spaced asubstantial distance from the substantially common plane of top rollsIla-13a and is located on the opposite side of such plane from that ofthe guide arm body 20a which carries the top rolls Ila-13a and, also,the pivot axis of guide arm 20 is spaced a substantial distancerearwardly of the drafting rolls 11-13, Ila-13a. Preferably, the guidearm pivot axis is spaced below the plane of all of the drafting rolls.

Thus, with the top rolls occupying the operative position shown in solidlines in FIG. 1, when a predetermined yieldable force is applied toguide arm 20, by means to be later described, and thus urges guide arm20 in a counterclockwise direction in FIGS. 1 and 3, such force istransmitted about the axis of pivot pins 22 and thus to the top draftingrolls'1la-13a in an inclined forward and downward direction with respectto the mean plane of the draft path of the textile material T passingthrough the drafting unit. It is apparent that, by applying the force tothe top feed roll 11a in this manner, the pressure is more efiective atthe nip of rolls 11, 11a than would be the case if the pressure wasdirected downwardly thereat in a direction substantially perpendicularof the mean plane of the draft path or in a direction inclineddownwardly and rearwardly with respect to the mean plane of the draftpath as has been the case heretofore. In instances in which the nip ofthe feed rolls is located closely above the rearmost surface of thebottom feed roll it is important that the pressure applied to the topfeed roll has a component of forward thrust or force as opposed tohaving only a downward or downward and rearward component of thrust.Otherwise, the top feed roll might have the effect of a wedge againstthe bottom feed roll, or in the event of the top roll having a yieldablecover or cot thereon, the top roll might slip downwardly relative to thebottom feed roll.

Suitable means is provided for removably securing bracket 21 on anelongate shaft 25 which may extend past the rear portions of a pluralityof drafting units of the type heretofore described and which are usuallyprovided on a single roving or spinning machine. To this end, and ispreferred, the rear portions of the side walls of bracket 21 are eachprovided with a slot 21a separating the upper and lower portionsthereof, and opposite ends of upper and lower clamping bars 21b, 210 areconnected to or extend through the bracket side walls. Cam surfaces 21bon the proximal edge portions of clamping bars 21b, 21c, and adjacentthe elongate shaft 25, engage corresponding cam surfaces on a clampingblock or cam block 21e extending between the two clamping bars 21b, 21c.Clamping block 21c has an arcuate inner surface which is substantiallyof the same configuration as and engages the outer surface of theelongate shaft 25. A screw 21f loosely penetrates the lower clamping bar210 and threadedly penetrates the upper clamping bar 21b. Thus, it isapparent that the screw may be tightened to draw the opposing upper andlower portions of the bracket side walls toward each other while, at thesame time, the cam surfaces 2ld on clamping bars 21b, 21c engage the camsurfaces of clamping block 21e to cam the same against and tightlysecure the bracket 21 in the desired position on the elongate shaft 25.

Referring to FIGS. 1, 3 and 4, it will be observed that the elongatebody 20a of guide arm 20 includes depending spaced apart side walls orflanges 200 between which the upper portions of rear and front saddles26, 27 are positioned. The rear portion of rear saddle 26 (FIG. 7) issubstantially U-shaped in cross-section and the bridging lower wallthereof forms a slotted guideway 26a for receiving therein a bolt 30which adjustably secures thereto a rear holder or support block 11b fortop delivery roll 11a. As shown in FIGS. l-3, as is conventional, toprolls 11a, 12a, are journaled on shafts releasably mounted in thecorresponding holders or support blocks 11b, 12b, 13b.

The side walls or flanges of rear saddle 26 extend for wardly beyond theslotted guideway26a and have the upper portions of the side walls offront saddle 27 positioned therebetween. Front saddle 27 also issubstantially U-shaped in cross-section and the bridging lower wallthereof also forms a slotted guideway 27a for receiving bolts 32, 33therein to adjustably secure thereto the respective intermediate andfront holders or support blocks 12b, 13b for the respective intermediateand delivery top rolls 12a, 13a. To aid an operator in determining thedesired adjusted spacing of the top drafting rolls 11a, 12a, 13a, thelower portions of the side walls or flanges of saddles 26, 27, below theside walls of guide arm body 20a, may bear suitable. graduated indiciathereon, as shown in FIG. 1. Such indicia may be in the form of a metricscale.

The saddles 26, 27 are pivotally mounted in such a manner as tofacilitate changing the moment arm ratios thereof with respect to eachother and with respect to guide arm thereby varying the amount ofpressure applied to each top drafting roll Ila-13a without changing thepositions of the saddles relative to each other and relative to guidearm 20. To this end, the front upper portions of the guide arm sidewalls 20c and the side walls of rear saddle 26 are provided withlongitudinally extending rows of aligned, spaced, holes or bores 35, anda first saddle pivot pin 36 passes through an opposing set of the bores35 in guide arm side wall 20c and rear saddle 26 to pivotally mount rearsaddle 26 on guide arm 20. Pivot pin 36 may be selectively positioned inthe sets of aligned bores, three sets of which are shown in FIGS. 1, 3and 7, to thereby vary the position of the pivot axis of rear saddle 26relative to guide arm 20. Opposite ends of the pivot pin 36 may extendoutwardly beyond guide arm side walls 200 and may be suitably recessedfor receiving thereon suitable snap rings 35a (FIG. 4), preferably ofresilient material, for removably securing the pivot pin 36 in thedesired position.

The proximal overlapping portions of the side walls of saddles 26, 27also are provided with longitudinally extending rows of aligned, spacedholes or bores 40 therethrough, and a second saddle pivot pin 41 passesthrough an opposing set of bores 40 in saddles 26, 27 to pivotallyconnect the medial portion of front saddle 27 to a forward portion ofrear saddle 26. Although the sets of bores 40 are positioned in suchproximity to each other that they are in open communication with eachother, it is apparent that the scalloped upper and lower edges of theslots thus formed from the bores 40 constitute, to all intents andpurposes, definition of the aligned holes or bores 40. Thus, it isapparent that pivot pin 41 may be selectively positioned in the sets ofaligned bores 40 to thereby vary the position of the pivot axis of frontsaddle 27 relative to rear saddle 26 and guide arm to thereby vary theeffective pressure applied to each top drafting roll Ila-13a. It is thusseen that the first and second pivot pins 36, 41 are selectivelypositionable along guide arm 20 and rear saddle 26, respectively, forpivotally connecting rear saddle 26 to guide arm 20 and for pivotallyconnecting front saddle 27 to rear saddle 26 to vary the pivot axes ofthe rear and front saddles 26, 27 without changing the position of thesaddles relative to each other and relative to guide arm 20.

Utilizing an actual apparatus constructed according to the invention,different top roll pressures have been obtained by varying the positionsof pivot pins 36, 41 longitudinally of the saddles 26, 27 withoutshifting them longitudinally of guide arm 20 and without changing theamount of yieldable force applied to guide arm 20. For example, with theaxes of top intermediate roll 12a and top feed roll 11a spacedrearwardly from the axis of top delivery roll 47 millimeters (mm) and108 mm, respectively, pivot pin 36 (FIG. 3) was positioned in thefrontmost set of holes 35, and pivot pin 41 was positioned in the secondset of holes from the front as in FIG. 3. This resulted in loads of l3,l5 and 18 kilograms being applied to the respective top rolls 11a, 12a,13a. Simply by changing the position of pivot pin 41 to the frontmostset of holes 40, this changed the loads on top rolls 11a, 12a, 13a tol8, l0 and 20 kilograms, respectively.

As a further example, the roll spacing was changed so that the axes ofrolls 12a, 11a were spaced 70 mm and 144 mm, respectively, rearwardly ofthe axis of top delivery roll 13a, and pivot pins 36, 41 were positionedin the rearmost sets of holes 35, 40. This resulted in loads of l7, l5and 20 kilograms being applied to the respective top rolls 11a, 12a,13a.

Novel means are provided for applying pressure to guide arm 20 while itoccupys the lowered, operative position shown in solid lines in FIGS. 1and 3, and for releasing such pressure and retaining guide arm 20 andthe top drafting rolls carried thereby in the raised, inoperative,position shown in broken lines in FIG. 1. In this regard, twoembodiments of yieldable force means are shown in FIGS. 3 and 5 andFIGS. 8 and 9, respectively. The first embodiment utilizes a mechanicalspring means for the yieldable force means, and the second embodimentutilizes a pneumatic bag or tube for the yieldable force means. Eitherembodiment of the yieldable force means may be used with the samesupport bracket 21, guide arm 20 and the parts carried thereby, and withessentially the same releasable yieldable force transmitting means, tobe later described, with the exception of interchanging a relatively fewparts to convert one embodiment to the other. In fact, if desired, oneor more of the drafting units of a particular textile machine may beequipped with top roll loading systems of this invention utilizing themechanical spring type of yieldable force means, while one or moreothers of the drafting units of the same textile machine may be equippedwith top roll loading systems of this invention utilizing the pneumatictype of yieldable force means. To facilitate interchangeability of thetwo forms of yieldable force means, it is preferred that support shaft25 is of tubular form and is slotted along its length, preferably byproviding a slot or opening 25a (FIGS. 3 and 6) through its lower wallportion corresponding to each bracket 21, although support shaft 25 maybe solid when utilizing the mechanical spring means of the firstembodiment of the yieldable force means with the top roll loadingsystem.

The first embodiment of the yieldable force means comprises a coiledcompression spring 45 (FIG. 3) which encircles a plunger 45a whose rearportion is guide for longitudinal movement in an upstanding springabutment 21g positioned between the rear lower portions of the sidewalls of bracket 21. Spring abutment 21g may be formed integral with abottom wall portion 21h extending between and integral with the sidewalls of bracket 21.

The rear end of spring 45 bears against spring abutment 21g and thefront end thereof bears against an enlarged portion 45b of plunger 45a.The front end of plunger 450 may be bifurcated and provided with awedge-shaped forward portion 45c which bears against the grooved lowerleg of a substantially vertically extending lower lever 50 which is acomponent of the releasable yieldable force transmitting means. A medialportion of lower lever 50 is pivotally mounted on a pivot pin 500 whoseopposing end portions extend through suitable holes provided in the sidewalls of bracket 21 and may be retained therein by suitable snap rings50b (FIGS. 1 and 5). The upper portion of lower lever 50 (FIG. 3)overlaps the proximal lower portion of an upper lever 51, the upperportion of lower lever 50 being positioned forwardly of the lowerportion of upper lever 51 and preferably having a roller or follower 50cjournaled thereon for engaging the front surface of the lower portion ofupper lever 51. A me dial portion of upper lever 51 is also pivotallymounted on a pivot pin 51a which may be removably mounted in the sidewalls of bracket 21. Upper lever 51 is provided with a forwardlyprojecting downwardly facing cam surface 51b which is positioned abovethe pivot point or pin 51a of upper lever 51, and the upper portion oflever 51 is provided with an upper guide surface 510 thereon whichextends upwardly and rearwardly from the front extremity of cam surface51b and whose rear portion terminates adjacent shoulder means 21i formedby the side walls of bracket 21, which side walls straddle levers 50,51.

The yieldable force transmitting means further comprises a latch armbroadly designated at 54. Latch arm 54 comprises an elongate forward orhandle portion 54a which overlies the body 20a of guide arm 20. Latcharm 54 is preferably of inverted substantially U-shaped cross-sectionand is provided with a downwardly projecting rear portion 54b whichloosely penetrates the upper wall of guide arm 20 and is pivotallymounted on a pivot pin 54c extending between and positioned in the sidewalls or flanges 200 of guide arm 20. It is to be noted that pivot pin540 is positioned above and rearwardly of the cam surface 51b of upperlever 51. Positioned between the side walls of the lower portion 54b oflatch arm 54 is a locking element which preferably takes the form of aroller 54d rotatably mounted in the latch arm 54. Roller 54d is movablewith latch arm 54 about pivot pin 54c and the relationship of roller 54dand pivot pin 54c is such that, when roller 54d is engaging cam surface51b, the handle portion 54a of latch arm 54 is in engagement with theupper wall of the body 20a of guide arm 20 and the roller 51b will havemoved the upper lever 51 in a clockwise direction in FIG. 4 againstfollower 50c and in opposition to compression spring 45 thereby applyinga predetermined downward pressure to the body 20a of guide arm 20 forloading the top rolls of the drafting unit. On the other hand, when thelatch arm 54 is pivoted upwardly relative to guide arm 20, roller 54dmoves forwardly and upwardly out of engagement with cam surface 51b,thus releasing guide arm 20 and permitting cam surface 51b to movedownwardly and forwardly a relatively short distance to the extentpermitted by engagement of the lower portion of upper lever 51 with thefront surface of support shaft 25.

In this regard, since counterclockwise movement of upper lever 51 islimited by engagement thereof with shaft 25 when guide arm 20 isreleased, the effective pressure to be transmitted to guide arm 20 whenroller 54d is engaging cam surface 51d may be varied by adjustablyvarying the angular position of bracket 21 about support shaft 25 andrelative to bottom drafting roller 11, 12, 13. Thus, the overall load onthe top rolls 11a, 12a, 13a may be adjusted to some extent withoutnecessarily changing spring 45 or the position of either saddle pivotpin 36 or 41. It is to be noted that the upwardly projecting front edgeportion of bottom wall 21h of bracket 21 also serves to limit forwardmovement of the lower portion of lower lever 50, as is desirable tofacilitate installing bracket 21 on shaft 25, and removing bracket 21from shaft 25, with guide arm 20 thereon and with latch arm 54 mountedon guide arm 20. In fact, if desired, the upwardly projecting frontportion of the lower wall 21h of bracket 21 may be so positioned as tobe engaged by lever 50 at the same time as or before its roller 50cpushes lever 51 against shaft 25 upon roller 54d being moved out ofengagement with cam surface 51b,

To permit movement of latch arm 54 relative to guide arm 20 for applyingpressure to and releasing pressure from guide arm 20 and also facilitateutilizing the latch lever 54 for raising and lowering guide arm 20, atorsion spring 54c is coiled about pivot pin 54c and has one leg thereofengaging the lower surface of the top wall of body 20a of guide arm 20.The other leg of torsion spring 54e engages the upper edge of anabutment 54f integral with and projecting inwardly from a forwardportion of one of the side walls of the portion 54b of latch arm 54.

Thus, with the latch arm 54 occupying the operative position shown inFIG. 3, an operator may pivot the handle portion 54a upwardly relativeto latch arm 21) until roller 54d moves out of engagement with camsurface Slb of upper lever 51, whereupon torsion spring 54e will urgethe body of guide arm 20 upwardly against latch arm 54. During theupward pivotal movement of guide arm 20 and latch arm 54, follower orroller 54d may ride upon the arcuate guide surface 51c of upper lever51. Upon the guide arm 20 and latch arm 54 being moved upwardly apredetermined distance to the inoperative position shown in broken linesin FIG. 1, for example, an abutment means 51g (FIG. 3) on the opposingside walls of the relatively short lower portion 54b of latch arm 54 mayb moved into engagement with the shoulders Zli on the upper portions ofthe side walls of bracket 21 so as to support the guide arm 20 and itstop rolls 11a, 12a, 13a in the raised position independently of spring45 and the compound linkage embodied in levers 51B, 51. When the guidearm is to be returned to the lowered or operative position, the operatormay apply downward pressure to the body 20a of guide arm 20 as latch arm54 is pivoted upwardly relative to guide arm 20 to thereby release theabutment means 51b from the shoulders 21i of bracket 21, whereupon theroller 54b may again be guided upon the guide surface 51c on upper lever51 as the guide arm 20 is returned to the fully lowered or operativeposition and until roller 54d is again moved into engagement with camsurface 51b.

In most instances, pivot pin 41 is likely to be so positioned that, whenthe top rolls 11a, 12a, 13a are not being supported by bottom rolls11-13 or the stock passing therebetween, the rear portion of frontsaddle 27 tends to fall away from the guideway 26a of rear saddle 26, aswhen guide arm 20 occupies raised, inoperative, position or is beingmoved toward or away from the latter position. To avoid such conditionwithout interferring with that movement of front saddle 27 necessary toits intended function, it will be observed in FIGS. 3 and '7 that springmeans, in the form of a relatively light, small, inverted substantiallyU-shaped, leaf spring 27b, has one of its legs suitably attached to therear portion of guideway 27a of front saddle 27. The other, rear, leg ofspring 27b overlies and may rest upon the front portion of guideway 26aof rear saddle 26. Thus, rear saddle 26 may support the rear portion offront saddle 27 while guide arm 20 is raised, but

spring 27b permits front saddle 2'7 to move in either direction aboutits pivot pin 41 while guide arm 20 is being moved into operativeposition and while it occupies operative position. Spring 27b should belight so that it will have very little, if any, noticeable effect on thepressure being applied to the top rolls 11a, 12a, 13a

if spring 27b happens to come into contact with rear saddle 27 whileguide arms occupies operative position.

The second embodiment of the yieldable force means shown in FIGS. 8 and9 requires only very slight modification of the top roll loading systemas described heretofore. Therefore, those parts of the loading systemshown in FIGS. 8 and 9 which correspond to like parts shown in FIGS. 1-7will bear the same reference characters, where applicable.

The second embodiment of the yieldable force means comprises an elongatepliable air bag or tube 55 closed at its opposite ends and positionedwithin tubular support shaft 25. One end of pliable tube 55 has afitting 55a thereon (FIG. 9) for connecting the same to a conduit 55bextending from a suitably controlled source of compressed air, notshown. Fitting 55a may be in the form of a check valve through whichcompressed air may be introduced into tube 55 by means of a portable airhose, not shown, if desired. Within shaft 25, pliable tube 55 is engagedby the flanged upper portion of a plunger 550 which loosely penetratesthe corresponding slot a heretofore described. In this secondembodiment, the yieldable force transmitting means is modified withrespect to the first embodiment to the extent that the substantiallystraight lower lever 50 of FIG. 4 is replaced by a substantiallyL-shaped lever or bell crank 60. Conveniently, lever 60 may be pivotallymounted on the same pivot pin 50a as that used in the first embodimentfor mounting lever 50 on bracket 21. As is the case with respect tolever 50, the upper portion of lever 60 extends upwardly in overlappingrelation to and forwardly of the lower portion of the upper lever 51 andhas a roller 60c mounted therein for engaging the front surface of thelower portion of upper lever 51. However, the lower arm of lower lever60 extends rearwardly beneath tubular support shaft 25 and its rearupper portion is engaged by the lower end of plunger 55c. Thus, thepneumatic pressure in pliable tube 55 urges plunger 55c against lever60, thus tending to move the same in a clockwise direction in FIG. 8 toapply a rearward force to the upper portion of lever 60 against thelower portion of lever 51. It is apparent that the lever 51 operates inthe same manner when utilizing the second embodiment of the yieldableforce means shown in FIGS. 8 and 9 as is the case when utilizing thefirst embodiment of the yieldable force means which is best shown inFIG. 3. Accordingly, a further description thereof is deemedunnecessary.

In the drawings and specification, there have been set forth preferredembodiments of the invention and, although specific terms are employed,they are used in a generic and descriptive sense only and not forpurposes of limitation.

That which is claimed is:

1. A loading system for a drafting unit having a series of bottomdrafting rolls and a series of top drafting rolls defining a draft pathfor textile fibers being drafted therebetween, said loading systemcomprising a guide arm having a forward portion normally overlying saiddrafting rolls, a rear saddle pivotally connected to said forwardportion of said guide arm and including a first guideway on a rearportion thereof for adjustably receiving a holder for a feed roll ofsaid series of top rolls, a front saddle pivotally connected to aforward portion of said rear saddle and including a second guideway foradjustably receiving at least one other holder for an other roll of saidseries of top rolls, first and second pivot pins selectivelypositionable longitudinally along said guide arm and said rear saddle,respectively, for pivotally connecting said rear saddle to said guidearm and for pivotally connecting said front saddle to said rear saddleto vary the pivot axes of said rear and front saddles, means including abracket stationarily mounted rearwardly of said drafting rolls pivotallysupporting a rear portion of said guide arm on a pivot axis spaced asubstantial distance below and rearwardly of the plane of all of thedrafting rolls and positioned on the opposite side of the drafting rollsfrom that of said pivot pins, and releasable force applying means forapplying a generally downward pressure to said guide arm such that thelocation of said pivot axis of said guide arm causes the pressure onsaid guide arm to be transmitted to the top rolls in a downward andforward direction, and whereby the force applied to the top rolls may bevaried by varying the pivot axes of said saddles, said releasable forceapplying means comprising yieldable force means carried by said bracket,a lever pivotally mounted on said bracket and having a downwardly facingcam surface on its front portion above its pivot, means operativelyconnecting said lever to said yieldable force means so that said camsurface thereon is biased forwardly and downwardly, a latch arm having arear portion thereof pivotally connected to said guide arm on an axisabove and rearwardly of said cam sur face of said lever, a lockingroller carried by said latch arm and movable therewith into and out ofengagement with said cam surface, and the distance from the pivot axisof said latch arm to said locking roller being such that said lockingroller displaces said cam surface upwardly in opposition to saidyieldable force means when said top drafting rolls are in loadingrelation to said bottom drafting rolls.

2. A loading system according to claim 1, wherein said guide arm andsaid rear saddle are provided with means for receiving said first pivotpin and arranged to vary the position of the pivot axis of said rearsaddle longitudinally of said guide arm.

3. A loading system according to claim 1, wherein said rear saddle andsaid front saddle are provided with means for receiving said second pintherein and arranged to vary the position of the pivot axis of saidfront saddle longitudinally of said rear saddle.

4. A loading system according to claim 1, wherein said first and secondguideways of the respective rear and front saddles are disposed inproximal nonoverlapping relationship, and a leaf spring attached to arear portion of said second guideway and overlying a front portion ofsaid first guideway to limit downward movement of the rear portion ofsaid front saddle relative to said rear saddle whenever said guide armis swung upwardly manually to lift the top drafting rolls away from thebottom drafting rolls.

5. A loading system for a drafting unit for drafting textile fibers,said drafting unit having a series of top drafting rolls and a series ofbottom drafting rolls; said loading system comprising a guide arm, meansmounting said top rolls on a forward portion of said guide arm, asupport shaft extending generally parallel with said drafting rolls andspaced rearwardly from said drafting unit, a support bracket secured onsaid shaft and to which a rear portion of said guide arm is pivotallyconnected, compound linkage including an upper lever and a lower leverpivotally mounted on said bracket and having proximal overlappingportions with the upper portion of said lower lever positioned forwardlyof the lower portion of said upper lever, a forwardly projectingdownwardly facing cam surface on said upper lever above its pivot point,yieldable force means urging said lower lever in one direction about itspivot so that its upper portion engages and urges said upper lever inthe opposite direction about its pivot whereby said cam surface isbiased forwardly and downwardly, a latch arm pivotally mounted on saidguide arm on an axis above and rearwardly of said cam surface, a lockingelement carried by said latch arm and movable therewith into and out ofengagement with said cam surface, and the relationship of said lockingelement and the pivot of said latch arm being such that, when saidlocking element is engaging said cam surface, it biases said guide armdownwardly thereby loading the top rolls of the drafting unit andwhereby, by pivoting said latch arm upwardly relative to said guide arm,the top rolls may be relieved of the load thereon and said guide arm maybe pivoted upwardly and rearwardly about its pivot.

6. A loading system according to claim 5, wherein the pivot axis of saidguide arm is located at a lower portion of said bracket substantiallybelow the plane of the drafting rolls whereby yielding force istransmitted to the top rolls from said yieldable force means throughsaid guide arm in a downward and forward direction.

7. A loading system according to claim 5, wherein said bottom rollsinclude a bottom feed roll and said top rolls include a top feed rollwhich, when occupying an operative position, has its rotational axisspaced rearwardly of and above the rotational axis of said bottom feedroll, and wherein the pivot axis of said guide arm is located at a lowerportion of said bracket substantially below the mean plane of the pathof the fibers through the drafting unit whereby yielding force istransmitted to the top rolls from said yieldable force means throughsaid guide arm in a downward and forward direction to thereby urge saidtop feed roll downwardly and forwardly toward its nip with said bottomfeed roll.

8. A loading system according to claim 5, wherein said yieldable forcemeans comprises a spring carried by said bracket.

9. A loading system according to claim 5, wherein said yieldable forcemeans comprises a spring-loaded plunger movably supported by saidbracket and engaging and applying a forward force to said lower leverbelow its pivot.

10. A loading system according to claim 5, wherein said yieldable forcemeans comprises a coiled spring arranged to apply forward force to saidlower. lever below its pivot point, means limiting the extent ofrearward movement of the lower portion of said upper lever and thuslimiting the extent of forward and downward movement of said cam surfacewhen said locking element is out of engagement with said cam surface,and means adjustably securing said bracket on said support shaft forangular adjustment of said bracket about the axis of said support shaftto thereby permit adjustment of the position of said cam surfacerelative to said bottom drafting rolls whereby the load to be applied tosaid top rolls when said locking element is engaging said cam surfacemay be adjusted by angular adjustment of said bracket.

11. A loading system according to claim 5, wherein said support shaft istubular, and wherein said yieldable force means comprises a yieldablepneumatic tube in said support shaft adapted to contain compressed airtherein, and a plunger engaging said tube, loosely penetrating the wallof said shaft, and engaging said lower lever to apply a rearward forceto its upper portion against said upper lever.

12. A loading system according to claim 5, wherein said latch armincludes a handle portion overlying said guide arm, and spring meansbetween said latch arm and said guide arm arranged to apply a liftingforce to said guide arm when said latch arm is raised and said lockingelement is out of engagement with said cam surface.

13. A loading system according to claim 12, wherein said bracket isprovided with shoulder means thereon rearwardly of said upper lever, andabutment means on said latch arm engageable with said shoulder meanswhen said latch arm is raised a predetermined distance relative to saidcam surface on said upper lever to thereby support said guide arm andits top rolls in a raised position.

14. A loading system according to claim 13, wherein said upper lever isprovided with an upper guide surface thereon extending rearwardly fromsaid cam surface to a point adjacent said shoulder means for engagementby said locking element and arranged to guide said locking elementbetween said cam surface and said shoulder means during raising andlowering of said latch arm and said guide arm.

15. A loading system for a drafting unit having a series of bottomdrafting rolls and a series of top drafting rolls defining a draft pathfor textile fibers being drafted therebetween, said loading systemcomprising a guide arm having a forward portion normally overlying saiddrafting rolls, a rear saddle pivotally connected to said forwardportion of said guide arm and including a first guideway on a rearportion thereof for adjustably receiving a holder for a feed roll ofsaid series of top rolls, a front saddle pivotally connected to aforward portion of said rear saddle and including'a second guideway foradjustably receiving at least one other holder for another roll of saidseries of top rolls, first and second pivot pins selectivelypositionable longitudinally along said guide arm and said rear saddle,respectively, for pivotally connecting said rear saddle to said guidearm and for pivotally connecting said front saddle to said rear saddleto vary the pivot axes of said rear and front saddles, a support shaftextending generally parallel with said drafting rolls and spacedrearwardly of said drafting unit, a bracket secured on said shaft and towhich a rear portion of said guide arm is pivotally connected formovement on a pivot axis spaced a substantial distance below andrearwardly the plane of all of the drafting rolls and positioned on theopposite side of the drafting rolls from that of said pivot pins,compound linkage including an upper lever and a lower lever pivotallymounted on said bracket and having proximal overlapping portions withthe upper portion of said lower lever positioned forwardly of the lowerportion of said upper lever, a forwardly projecting downwardly facingcam surface on said upper lever above its pivot point, yieldable forcemeans urging said lower lever in one direction about its pivot so thatits upper portion engages and urges said upper lever in the oppositedirection about its pivot whereby said cam arm downwardly therebyloading the top rolls of the drafting unit whereby the location of saidpivot axis of said guide arm causes the pressure on said guide arm to betransmitted to the top rolls in a downward and forward direction, andwhereby the force applied to the top rolls may be varied by varying thepivot axes of said saddles.

* i i t

1. A loading system for a drafting unit having a series of bottomdrafting rolls and a series of top drafting rolls defining a draft pathfor textile fibers being drafted therebetween, said loading systemcomprising a guide arm having a forward portion normally overlying saiddrafting rolls, a rear saddle pivotally connected to said forwardportion of said guide arm and including a first guideway on a rearportion thereof for adjustably receiving a holder for a feed roll ofsaid series of top rolls, a front saddle pivotally connected to aforward portion of said rear saddle and including a second guideway foradjustably receiving at least one other holder for another roll of saidseries of top rolls, first and second pivot pins selectivelypositionable longitudinally along said guide arm and said rear saddle,respectively, for pivotally connecting said rear saddle to said guidearm and for pivotally connecting said front saddle to said rear saddleto vary the pivot axes of said rear and front saddles, means including abracket stationarily mounted rearwardly of said drafting rolls pivotallysupporting a rear portion of said guide arm on a pivot axis spaced asubstantial distance below and rearwardly of the plane of all of thedrafting rolls and positioned on the opposite side of the drafting rollsfrom that of said pivot pins, and releasable force applying means forapplying a generally downward pressure to said guide arm such that thelocation of said pivot axis of said guide arm causes the pressure onsaid guide arm to be transmitted to the top rolls in a downward andforward direction, and whereby the force applied to the top rolls may bevaried by varying the pivot axes of said saddles, said releasable forceapplying means comprising yieldable force means carried by said bracket,a lever pivotally mounted on said bracket and having a downwardly facingcam surface on its front portion above its pivot, means operativelyconnecting said lever to said yieldable force means so that said camsurface thereon is biased forwardly and downwardly, a latch arm having arear portion thereof pivotally connected to said guide arm on an axisabove and rearwardly of said cam surface of said lever, a locking rollercarried by said latch arm and movable therewith into and out ofengagement with said cam surface, and the distance from the pivot axisof said latch arm to said locking roller being such that said lockingroller displaces said cam surface upwardly in opposition to saidyieldable force means when said top drafting rolls are in loadingrelation to said bottom drafting rolls.
 2. A loading system according toclaim 1, wherein said guide arm and said rear saddle are provided withmeans for receiving said first pivot pin and arranged to vary theposition of the pivot axis of said rear saddle longiTudinally of saidguide arm.
 3. A loading system according to claim 1, wherein said rearsaddle and said front saddle are provided with means for receiving saidsecond pin therein and arranged to vary the position of the pivot axisof said front saddle longitudinally of said rear saddle.
 4. A loadingsystem according to claim 1, wherein said first and second guideways ofthe respective rear and front saddles are disposed in proximalnon-overlapping relationship, and a leaf spring attached to a rearportion of said second guideway and overlying a front portion of saidfirst guideway to limit downward movement of the rear portion of saidfront saddle relative to said rear saddle whenever said guide arm isswung upwardly manually to lift the top drafting rolls away from thebottom drafting rolls.
 5. A loading system for a drafting unit fordrafting textile fibers, said drafting unit having a series of topdrafting rolls and a series of bottom drafting rolls; said loadingsystem comprising a guide arm, means mounting said top rolls on aforward portion of said guide arm, a support shaft extending generallyparallel with said drafting rolls and spaced rearwardly from saiddrafting unit, a support bracket secured on said shaft and to which arear portion of said guide arm is pivotally connected, compound linkageincluding an upper lever and a lower lever pivotally mounted on saidbracket and having proximal overlapping portions with the upper portionof said lower lever positioned forwardly of the lower portion of saidupper lever, a forwardly projecting downwardly facing cam surface onsaid upper lever above its pivot point, yieldable force means urgingsaid lower lever in one direction about its pivot so that its upperportion engages and urges said upper lever in the opposite directionabout its pivot whereby said cam surface is biased forwardly anddownwardly, a latch arm pivotally mounted on said guide arm on an axisabove and rearwardly of said cam surface, a locking element carried bysaid latch arm and movable therewith into and out of engagement withsaid cam surface, and the relationship of said locking element and thepivot of said latch arm being such that, when said locking element isengaging said cam surface, it biases said guide arm downwardly therebyloading the top rolls of the drafting unit and whereby, by pivoting saidlatch arm upwardly relative to said guide arm, the top rolls may berelieved of the load thereon and said guide arm may be pivoted upwardlyand rearwardly about its pivot.
 6. A loading system according to claim5, wherein the pivot axis of said guide arm is located at a lowerportion of said bracket substantially below the plane of the draftingrolls whereby yielding force is transmitted to the top rolls from saidyieldable force means through said guide arm in a downward and forwarddirection.
 7. A loading system according to claim 5, wherein said bottomrolls include a bottom feed roll and said top rolls include a top feedroll which, when occupying an operative position, has its rotationalaxis spaced rearwardly of and above the rotational axis of said bottomfeed roll, and wherein the pivot axis of said guide arm is located at alower portion of said bracket substantially below the mean plane of thepath of the fibers through the drafting unit whereby yielding force istransmitted to the top rolls from said yieldable force means throughsaid guide arm in a downward and forward direction to thereby urge saidtop feed roll downwardly and forwardly toward its nip with said bottomfeed roll.
 8. A loading system according to claim 5, wherein saidyieldable force means comprises a spring carried by said bracket.
 9. Aloading system according to claim 5, wherein said yieldable force meanscomprises a spring-loaded plunger movably supported by said bracket andengaging and applying a forward force to said lower lever below itspivot.
 10. A loading system according to claim 5, wherein said yieldableforce means comprises a coiled spring arranged to apply forward force tosaid lower lever below its pivot point, means limiting the extent ofrearward movement of the lower portion of said upper lever and thuslimiting the extent of forward and downward movement of said cam surfacewhen said locking element is out of engagement with said cam surface,and means adjustably securing said bracket on said support shaft forangular adjustment of said bracket about the axis of said support shaftto thereby permit adjustment of the position of said cam surfacerelative to said bottom drafting rolls whereby the load to be applied tosaid top rolls when said locking element is engaging said cam surfacemay be adjusted by angular adjustment of said bracket.
 11. A loadingsystem according to claim 5, wherein said support shaft is tubular, andwherein said yieldable force means comprises a yieldable pneumatic tubein said support shaft adapted to contain compressed air therein, and aplunger engaging said tube, loosely penetrating the wall of said shaft,and engaging said lower lever to apply a rearward force to its upperportion against said upper lever.
 12. A loading system according toclaim 5, wherein said latch arm includes a handle portion overlying saidguide arm, and spring means between said latch arm and said guide armarranged to apply a lifting force to said guide arm when said latch armis raised and said locking element is out of engagement with said camsurface.
 13. A loading system according to claim 12, wherein saidbracket is provided with shoulder means thereon rearwardly of said upperlever, and abutment means on said latch arm engageable with saidshoulder means when said latch arm is raised a predetermined distancerelative to said cam surface on said upper lever to thereby support saidguide arm and its top rolls in a raised position.
 14. A loading systemaccording to claim 13, wherein said upper lever is provided with anupper guide surface thereon extending rearwardly from said cam surfaceto a point adjacent said shoulder means for engagement by said lockingelement and arranged to guide said locking element between said camsurface and said shoulder means during raising and lowering of saidlatch arm and said guide arm.
 15. A loading system for a drafting unithaving a series of bottom drafting rolls and a series of top draftingrolls defining a draft path for textile fibers being draftedtherebetween, said loading system comprising a guide arm having aforward portion normally overlying said drafting rolls, a rear saddlepivotally connected to said forward portion of said guide arm andincluding a first guideway on a rear portion thereof for adjustablyreceiving a holder for a feed roll of said series of top rolls, a frontsaddle pivotally connected to a forward portion of said rear saddle andincluding a second guideway for adjustably receiving at least one otherholder for another roll of said series of top rolls, first and secondpivot pins selectively positionable longitudinally along said guide armand said rear saddle, respectively, for pivotally connecting said rearsaddle to said guide arm and for pivotally connecting said front saddleto said rear saddle to vary the pivot axes of said rear and frontsaddles, a support shaft extending generally parallel with said draftingrolls and spaced rearwardly of said drafting unit, a bracket secured onsaid shaft and to which a rear portion of said guide arm is pivotallyconnected for movement on a pivot axis spaced a substantial distancebelow and rearwardly the plane of all of the drafting rolls andpositioned on the opposite side of the drafting rolls from that of saidpivot pins, compound linkage including an upper lever and a lower leverpivotally mounted on said bracket and having proximal overlappingportions with the upper portion of said lower lever positioned forwardlyof the lower portion of said upper lever, a forwardly projectingdownwardly facing cam surface on said upper lever above its pivot point,yieldable Force means urging said lower lever in one direction about itspivot so that its upper portion engages and urges said upper lever inthe opposite direction about its pivot whereby said cam surface isbiased forwardly and downwardly, a latch arm pivotally mounted on saidguide arm on an axis above and rearwardly of said cam surface, a lockingelement carried by said latch arm and movable therewith into and out ofengagement with said cam surface, and the relationship of said lockingelement and the pivot of said latch arm being such that, when saidlocking element is engaging said cam surface, it biases said guide armdownwardly thereby loading the top rolls of the drafting unit wherebythe location of said pivot axis of said guide arm causes the pressure onsaid guide arm to be transmitted to the top rolls in a downward andforward direction, and whereby the force applied to the top rolls may bevaried by varying the pivot axes of said saddles.